Thursday, March 28, 2013

We're nearing the end of what, by National Weather Service standards, will be the coldest March in Charlotte in more than 40 years.

The Weather Service measures monthly temperatures by compiling daily averages. In other words, you take the daily high and low temperatures, and get an average for the day. And for the month, you get an average of the daily averages.

By that measurement, we're on pace for the fifth or sixth coldest March in Charlotte history, somewhere around 5 degrees below average.

But here's another way of measuring just how miserable it has been in recent weeks -- by looking at afternoon high temperatures.

Most people don't have to deal with morning low temperatures. They're snug and warm, inside their homes or possibly already at work. Afternoon highs are a different story. We're walking home from school, getting in our cars to come home from work, trying to play scholastic or amateur sports, or doing any of a number of other things.

The point is ... we're out there, in it.

I've taken a look at how our afternoon high temperatures in Charlotte have compared to the daily averages, and the pattern is obvious.

We were mild for the beginning of winter -- through December and January, and into the middle of February. That's when a high-latitude blocking pattern became established, creating a kink in the jet stream that sent repeated bursts of polar air into the eastern United States.

Here's how our daily highs have compared to average:

DECEMBER ... 24 days above average; 7 days below.

JANUARY ... 18 days above average; 3 days average; 10 days below.

FEBRUARY ... 11 days above average; 17 days below.

MARCH ... 8 days above average; 20 days below.

So since Dec. 1, we've had above-average daytime temperatures about 55 percent of the time.

Now here's the interesting statistic:

SINCE FEB. 15 ... 10 days above average; 31 days below.

In other words, since the middle of last month, our daytime highs have been below average about 75 percent of the time. And on many of those days, highs were well below average.

It's a statistical look at the reason why many people are eagerly awaiting a warm-up.

About this blog

Steve Lyttle says growing up in northeastern Ohio, with its foot-deep snows and summertime severe thunderstorms, fueled his interest in meteorology. He has written about weather for 10 years at The Observer. Join the discussion about weather trends and weird weather events -- whether local or around the world.